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Black swan events are highly improbable events that nevertheless occur, and drive risk estimation in stock market collapses, earthquake frequency, and deaths from the largest wars. But how often do animal populations exhibit surprisingly large booms and busts? A new study finds strong evidence for black swan events in about 4% of animal populations, typically driven by climate, severe winters, predators and parasites.

The natural pattern of river flows, with frequent flood events, has been substantially altered worldwide through dams and other forms of water diversion for human uses. A new modeling study now shows that changing historical flow patterns results in simplified interactions between plant species in and around rivers, and the replacement of large riverside trees with shrubs. These changes to plant species are influenced by the loss of frequent floods, increased droughts, and a river flow pattern that is more stable than is normal.

Native oysters are important players in many nearshore ocean ecosystems, but their numbers are declining worldwide. Restoration success depends on how well oysters survive when transplanted to new habitats. In a new experiment, native Olympia oysters were transplanted among oyster regions in Puget Sound in a reciprocal fashion to see how this affected their survival, growth, and reproduction. There were substantial differences in each small population of Olympia oysters within Puget Sound, providing information on which source population would be best suited for broad-scale oyster restoration in the region.

Fish catch limits are set based on the results of complex fisheries stock assessment models, which are somewhat like weather forecast models, but for fish populations. An examination of historical assessments of Australian fisheries has determined that there is considerable uncertainty in estimates of fish biomass, with a 95% chance that stock assessment estimates of spawning biomass are within half to double of the best estimates.

Endangered whooping cranes form long-term monogamous bonds, but it has not previously been known when these pair bonds first form. New data now reveals that 62% of breeding pairs actually form more than a full year before breeding, and 28% of breeding pairs begin to “date” more than two years before breeding starts. These findings suggest there are substantial benefits to partnering in addition to breeding, perhaps to support each other when competing with other birds or to increase partner familiarity.

The Tonle Sap Lake in Cambodia is a seasonal wetland that floods every year during the rainy season. New research examining the isotope ratios in carbon, sulfur, and nitrogen in fish, shows that fish species benefit greatly from this flooding because it expands their access to new and different types of food contained in the newly flooded areas. The resulting highly diverse assemblage of fish species are the basis of a productive fishery that is a major provider of food in the region, which will be impacted in uncertain ways by the planned construction of more than 200 dams in the greater Mekong River Basin that feeds Tonle Sap Lake.

Chinook salmon on the Snake and Columbia rivers face challenges, notably navigating through hydropower systems, during their migration from freshwater to the ocean; these experiences may change their survival in the ocean. A recent laboratory experiment compared Chinook salmon that were barged through five or seven dams (experiencing cooler temperatures) to those that swim through the hydropower system (experiencing warmer temperatures).

A new series of laboratory experiments on Chinook salmon reveals the effect of warmer freshwater on the time from egg hatching to emergence from gravel as fry. Warmer water resulted in fry emerging two and a half months earlier than those exposed to cooler water, after accounting for genetic differences among eggs produced by different combinations of parental fish. The newly emerged fry were also less developed on emergence when exposed to warm water.

A new study uses two decades of tagging data on beluga whales to identify habitats that they prefer. In the eastern Chukchi and eastern Beaufort Seas, belugas preferred places with particular depth features, like canyons and continental slopes, instead of preferring places based on sea ice characteristics. Thus while reduced sea ice in this region may indirectly affect belugas through ecosystem changes, they did not rely on sea ice features to find places with good food availability.

Seafood consumers are increasingly interested in buying seafood that has a sustainable ecolabel certification by companies such as the Marine Stewardship Council. A new study identifies a key reason why it is so difficult for retailers to get a price premium for ecolabeled seafood: people differ widely in their willingness to pay more for ecolabels. In particular, those who might be happy to pay a lot more for sustainably labeled seafood, may not be willing to pay a lot for seafood relative to other protein such as chicken, pork, or beef.